The correct statement regarding the Kingdom of Mali of West Africa is:
B. It controlled trade routes which had previously been controlled by the Kingdom of Ghana.
The Kingdom of Mali, which rose to prominence in the 13th century, took control of significant trade routes across the Sahara, particularly those that linked West Africa with North Africa and facilitated the trade of gold, salt, and other goods. While it did engage in trade with other regions, it was primarily known for its control over the trans-Saharan trade routes, which had been previously dominated by the Kingdom of Ghana.